Grill shutter device

ABSTRACT

A shutter mechanism is adapted to be provided to a grill opening in a vehicle body. Opening and closing operations of the shutter mechanism are controlled by an electronic control unit (ECU). The ECU determines whether a vehicle is in a traveling end state. If the vehicle is in the traveling end state, the ECU determines whether or not the shutter mechanism is in an open state. If the ECU determines that the open state of the shutter mechanism cannot be confirmed, the ECU controls the shutter mechanism to open the shutter mechanism.

TECHNICAL FIELD

The present invention relates to a grill shutter device.

BACKGROUND ART

Patent Document 1 discloses a grill shutter device that can control theflow rate of air flowing from grill opening into an engine compartmentaccording to opening and closing operations of shutter mechanismprovided in the grill opening in the front portion of a vehicle body.

In the grill shutter device, for example, when the vehicle is travellingat high speed, the shutter mechanism is closed and the air flowing intothe engine compartment is limited so that the aerodynamic performance(such as Cd value) of the vehicle can be improved. When starting theengine, the flow rate of the air introduced into the radiator is limitedso that the warm-up time of the engine is reduced. Further, when theengine temperature tends to be increased, the shutter mechanism isopened so that the flow rate of the air flowing into the enginecompartment is increased. Accordingly, the engine temperature isappropriately controlled.

Generally, such a grill shutter device is configured to open the shuttermechanism after usual opening and closing controls of the shuttermechanism is completed by turning off the ignition switch. That is, theshutter mechanism is closed when the vehicle is in the stopped state.This restricts the shutter mechanism from being stuck into the closedstate. Further, Patent Document 1 discloses a configuration for forciblyterminating the opening and closing controls of the shutter mechanism toopen the shutter mechanism when the voltage supplied to the drivingmotor of the shutter mechanism is reduced. This avoids the situation inwhich the amount of the air flowing into the vehicle is insufficient dueto the stuck closed state of the shutter mechanism as described above.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: Japanese Laid-Open Patent Publication No.    2010-260440

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

However, as the opening and closing operations of the shutter mechanismis increased, the period of endurance of the shutter mechanism tends tobe reduced. Such a tendency is eminent when a load is applied to theshutter mechanism more than needed, for example, when the already openedshutter mechanism is further opened. Accordingly, there is a room forimprovement regarding this point.

An objective of the present invention is to provide a grill shutterdevice by which a shutter mechanism is more reliably prevented frombeing held stopped in the closed state and an excessive operation islimited so that the period of endurance is prolonged.

Means for Solving the Problems

To achieve the above described object, the present invention provides agrill shutter device that includes a shutter mechanism, a controlportion, a traveling end determination portion, and a confirmationportion. The shutter mechanism is adapted to be provided in a grillopening in a front portion of a vehicle body. The shutter mechanism isoperated to be opened and closed to control a rate of flow of an airflowing into the vehicle body. The control portion controls opening andclosing operations of the shutter mechanism. The traveling enddetermination portion determines whether a vehicle is in a traveling endstate. The confirmation portion confirms that the shutter mechanism isin an open state in the traveling end state. The control portioncontrols the shutter mechanism to open the shutter mechanism when theopen state of the shutter mechanism is not confirmed by the confirmationportion.

According to the present invention, after the end of the traveling ofthe vehicle, if the open state of the shutter mechanism is notconfirmed, the shutter mechanism is controlled to be opened.Accordingly, the shutter mechanism is more reliably prevented from beingheld stopped in the closed state. In contrast, if the open state of theshutter mechanism is confirmed after the end of the traveling of thevehicle, the opening operation control is not performed. Accordingly, anexcessive operation of the shutter mechanism is limited so that theperiod of endurance is prolonged.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a vehicle on which agrill shutter device according to the present invention is mounted;

FIG. 2 is a block diagram illustrating a control of the grill shutterdevice according to a first embodiment;

FIG. 3 is a flowchart illustrating a control process of the grillshutter device in FIG. 2;

FIG. 4 is a block diagram illustrating a control of a grill shutterdevice according to a second embodiment;

FIG. 5 is a flowchart illustrating a control process of the grillshutter device in FIG. 4;

FIG. 6 is a diagram schematically illustrating a configuration of adisconnection detection circuit in the grill shutter device in FIG. 4;

FIG. 7 is a flowchart illustrating a control process of a grill shutterdevice according to a third embodiment; and

FIG. 8 is a flowchart illustrating a control process of a grill shutterdevice according to another embodiment.

MODES FOR CARRYING OUT THE INVENTION First Embodiment

A description will be given below of a first embodiment of the presentinvention with reference to the accompanying drawings.

In a vehicle 1 shown in FIG. 1, an engine compartment 3 formed in avehicle body 2 accommodates an engine 4 and a radiator (heat exchanger)5 for cooling the engine 4. A grill opening 7 that connects an outerspace in front of the vehicle 1 with an inner space (engine compartment3) of the vehicle body 2 is formed in the front portion of the vehiclebody 2 (the left end in FIG. 1). The radiator 5 is arranged in front ofthe engine 4 such that the air flowing from the grill opening 7 into theengine compartment 3 blows against the radiator 5.

A fan 6 is provided behind the radiator 5 (right as viewed in FIG. 1).When the fan 6 rotates, the air efficiently flows to the radiator 5.

According to the present embodiment, the grill opening 7 is formed belowa bumper 8. A front grill (lower grill) 9, which forms an ornamentalsurface, is attached to an opening edge 7 a of the grill opening 7. Thevehicle 1 according to the present embodiment includes a grill shutterdevice 10, which controls the flow rate of the air flowing from thegrill opening 7 into the engine compartment 3.

More specifically, the grill shutter device 10 includes a shuttermechanism 11, which controls the flow rate of the air through theopening and closing operations of the shutter mechanism 11, and anactuator portion 12, which opens and closes the shutter mechanism 11.

The shutter mechanism 11 includes a frame 13, which is shaped insubstantially a rectangular frame, and a plurality of movable fins 14,which are vertically aligned in an opening region defined by the frame13. The frame 13 is arranged in the grill opening 7 in such a statewhere the upper end of the frame 13 is fixed to a bumper reinforcingmember 15. Each movable fin 14 includes a rotary shaft 16, which extendsin the widthwise direction of the frame 13 (a direction perpendicular tothe sheet of FIG. 1) and is rotationally supported by the frame 13. Eachmovable fin 14 includes a fin portion 17, which rotates about the axisof the rotary shaft 16 along with the rotary shaft 16. The fin portion17 opens and closes the opening region of the frame 13 in accordancewith the rotation.

The shutter mechanism 11 is configured such that it comes into the openstate in which the opening region of the frame 13 is opened and theclosed state in which the opening region is closed. FIG. 1 shows theshutter mechanism 11 in the closed state. Each movable fin 14 rotates inthe clockwise direction in FIG. 1 from the state shown in FIG. 1 untilthe fin portion 17 is substantially parallel to the direction of the airflowing from the grill opening 7. This brings the shutter mechanism 11into the open state. In contrast, when each movable fin 14 rotates inthe counterclockwise direction in FIG. 1 from the open state of theshutter mechanism 11, the shutter mechanism 11 is brought into theclosed state shown in FIG. 1. When each movable fin 14 is in therotation position corresponding to the closed state, the opening regionof the frame 13 is closed by stacked tip ends of the movable fins 14that are adjacent to each other.

As shown in FIG. 2, an actuator portion 12 rotates each movable fin 14with a motor 18, which serves as a drive source, to drive the shuttermechanism 11 to be opened and closed. The actuator portion 12 iscontrolled by an ECU 20, which serves as a control portion.

That is, the ECU 20 controls the opening and closing operations of theshutter mechanism 11 through the control of the actuator portion 12. Thegrill shutter device 10 controls the flow rate of the air flowing fromthe grill opening 7 into the engine compartment 3 according to theopening and closing operations of the shutter mechanism 11 by therotation of each movable fin 14.

The ECU 20 is configured such that various types of vehicle statequantity such as vehicle speed V and a temperature Tw of the coolant ofthe engine 4 is input into the ECU 20. The ECU 20 performs the openingand closing controls of the shutter mechanism 11 on the basis of thevehicle state quantity.

Specifically, when communication of the various types of the vehiclestate quantity via an in-vehicle network 21 is started, the ECU 20recognizes that the ignition switch (start switch) of the vehicle 1 hasbeen turned ON (IG ON). That is, the ECU 20 recognizes that the vehicle1 is in the traveling state or in the traveling preparation state. Inother words, when the communication of the various types of the vehiclestate quantity via the in-vehicle network 21 is started, the ECU 20recognizes that the vehicle 1 is in the operation state (or the vehicle1 is powered on). The ECU 20 performs well-known opening and closingoperations such as holding the shutter mechanism 11 in the closed stateuntil the temperature Tw of the coolant is increased to an acceptablevalue, or switching the shutter mechanism 11 to the closed state inaccordance with the increase of the vehicle speed V.

Further, when the communication of the various types of the vehiclestate quantity via the in-vehicle network 21 is stopped, the ECU 20recognizes that the ignition switch of the vehicle 1 is turned OFF (IGOFF). That is, the ECU 20 recognizes that the vehicle 1 is in thetraveling end state. In other words, when the communication of thevarious types of the vehicle state quantity via the in-vehicle network21 is disconnected, the ECU 20 recognizes that the vehicle 1 is in theoperation end state (or the vehicle 1 is powered off). Further, the ECU20 confirms whether the shutter mechanism 11 is in the open state on thebasis of the detection of an amount of the operations of the shuttermechanism 11 when the vehicle 1 is in the traveling end state.Specifically, the actuator portion 12 includes a pulse sensor 22, whichserves as a pulse output portion for outputting pulse signals Sp insynchronization with the rotation of the motor 18. The ECU 20, whichserves as an operation amount detection portion, detects the amount ofthe operations of the shutter mechanism 11 by counting the pulse signalsSp (specifically, edges of the pulse signals Sp). If the ECU 20 does notconfirm that the shutter mechanism 11 is in the open state, the ECU 20controls the actuator portion 12 to open the shutter mechanism 11.

More specifically, as shown in the flowchart of FIG. 3, the ECU 20determines whether the vehicle 1 is in the traveling end state (stepS101). If the vehicle 1 is not in the traveling end state (i.e., NO instep S101), the ECU 20 continues the usual opening and closing controlson the basis of the temperature Tw of the coolant and the vehicle speedV (step S102). If the vehicle 1 is in the traveling end state (i.e., YESin step S101), the ECU 20 performs an open state confirmation processshown in the following steps S103 to S108.

Specifically, the ECU 20, which serves as a confirmation portion,determines whether the previous operation of the shutter mechanism 11was an opening operation in step S103. Also, in step S104, the ECU 20determines whether the number of counted pulses in the previousoperation of the shutter mechanism 11 is normal. That is, the ECU 20determines whether the amount of the operations of the shutter mechanism11 in the previous operation was normal. Specifically, the ECU 20 storesa normal pulse value as a preset normal amount of operations, anddetermines whether the number of counted pulses in the previousoperation of the shutter mechanism 11 was the normal pulse value. Thatis, the ECU 20 determines whether the amount of the operations of theshutter mechanism 11 in the previous operation was the normal amount ofoperations. The normal pulse value (amount of normal operations) may bea value showing a single number of counted pulses (amount ofoperations), or values showing an acceptable range of the numbers ofcounted pulses (amount of operations) that can be considered as normal.In step S105, the ECU 20 determines whether there has been a change inthe pulse signals Sp, that is, whether the pulses have occurred, afterthe previous operation of the shutter mechanism 11 is completed.

In step S106, the ECU 20 determines whether the pulse signal Sp detectedin the previous operation of the shutter mechanism 11 was normal. Thepulse sensor 22 of the present embodiment is configured to output twopulse signals Sp generated by two Hall ICs. If any one of the two pulsesignals Sp fails, the ECU 20, which serves as a pulse fault detectionportion and a signal determination portion, determines that the pulsesensor 22 fails. That is, the ECU 20 determines that the pulse signalsSp supplied by the pulse sensor 22 are not normal (i.e., NO in stepS106).

If all the determination conditions shown in steps S103, S104, and S106are satisfied (i.e., YES in steps S103, S104, and S106) and thedetermination result in step S105 is NO, the ECU 20 confirms that theshutter mechanism 11 is in the open state (step S107). In contrast, ifany of the determination conditions shown in steps S103, S104, and S106is not satisfied (i.e., NO in any of steps S103, S104, and S106), or ifthe determination result in step S105 is YES, the ECU 20 determines thatthe open state of the shutter mechanism 11 cannot be confirmed (stepS108).

If the ECU 20 determines that the open state of the shutter mechanism 11cannot be confirmed in step S108, the ECU 20 controls the shuttermechanism 11 to open the shutter mechanism 11. That is, the ECU 20performs an opening operation control after the end of traveling of thevehicle (step S109).

The opening operation control continues until a predetermined stopcondition (step S110) is satisfied. In the present embodiment, elapse ofa predetermined time from the start of the opening control operation isset as a predetermined stop condition. If the stop condition issatisfied (i.e., YES in step S110), the ECU 20 suspends the control ofthe shutter mechanism 11 (step S111).

In contrast, if the ECU 20 confirms the open state of the shuttermechanism 11 in above step S107, the ECU 20 suspends the control of theshutter mechanism 11 in step S111 without performing the openingoperation control after the end of traveling of the vehicle shown inabove steps S109 and S110.

That is, if the previous operation was not the opening operation (i.e.,NO in step S103), the shutter mechanism 11 is not in the open state.Even if the previous operation was the opening operation, if the amountof operations of the shutter mechanism 11 in the immediately previousopening operation is not normal (i.e., NO in step S104), the shuttermechanism 11 is likely to be not in the open state. If the pulses aregenerated after the end of the previous operation of the shuttermechanism 11 (i.e., YES in step S105), each movable fin 14 may have beenrotated by external force. That is, the shutter mechanism 11 is mostlikely to be not in the open state. Further, if the pulse signals Spused as a basis of the detection of the amount of operations of theshutter mechanism 11 are not normal (i.e., NO in step S106), it cannotbe confirmed that the shutter mechanism 11 is in the open state. The ECU20 can perform an open state confirmation through the abovedetermination process with high accuracy.

The present embodiment has the following advantages.

(1) The ECU 20 controls the opening and closing operations of theshutter mechanism 11. The ECU 20 determines whether or not the vehicle 1is in the traveling end state (step S101), and if the vehicle 1 is inthe traveling end state (i.e., YES in step S101), the ECU determineswhether or not the shutter mechanism 11 is in the open state (steps S103to S108). If the ECU 20 determines that the open state of the shuttermechanism 11 cannot be confirmed (step S108), the ECU 20 controls theshutter mechanism 11 to open the shutter mechanism 11 (step S109).

As mentioned above, in the present embodiment, after the end oftraveling of the vehicle, if the open state of the shutter mechanism 11cannot be confirmed, the shutter mechanism 11 is controlled to beopened. Accordingly, the shutter mechanism is more reliably preventedfrom being held stopped in the closed state. In contrast, after the endof traveling of the vehicle, if the open state of the shutter mechanism11 is confirmed, the opening operation control is not performed.Accordingly, an excessive operation of the shutter mechanism 11 islimited so that the period of endurance is prolonged.

(2) If the previous operation of the shutter mechanism 11 was not theopening operation (i.e., NO in step S103), the ECU 20 determines thatthe open state of the shutter mechanism 11 cannot be confirmed (stepS108), and performs the opening operation control after the end oftraveling of the vehicle (step S109).

That is, if the previous operation was no the opening operation, theshutter mechanism 11 is not in the open state. Therefore, according tothe above configuration, the open state of the shutter mechanism 11 isconfirmed with high accuracy.

(3) If the number of counted pulses in the previous operation was notnormal (i.e., NO in step S104), the ECU 20 determines that the openstate of the shutter mechanism 11 cannot be confirmed (step S108), andperforms the opening operation control after the end of traveling of thevehicle (step S109).

That is, if the amount of operations of the shutter mechanism 11 in theimmediately previous opening operation was not normal, the shuttermechanism 11 is likely to be not in the open state. Therefore, accordingto the above configuration, the open state of the shutter mechanism 11is confirmed with high accuracy.

(4) If the pulses are generated after the end of the previous operationof the shutter mechanism 11 (i.e., YES in step S105), the ECU 20determines that the open state of the shutter mechanism 11 cannot beconfirmed (step S108), and performs the opening operation control afterthe end of traveling of the vehicle (step S109).

That is, if the pulses are generated after the end of the previousoperation of the shutter mechanism 11, i.e., if the pulse signals arechanged, each movable fin 14 may have been rotated by the externalforce. That is, the shutter mechanism 11 is most probably not in theopen state. Therefore, according to the above configuration, the openstate of the shutter mechanism 11 is confirmed with high accuracy.

(5) If the detected pulse signals Sp are not normal (i.e., NO in stepS106), the ECU 20 determines that the open state of the shuttermechanism 11 cannot be confirmed (step S108), and performs the openingoperation control after the end of traveling of the vehicle (step S109).

That is, if the pulse signals Sp used as a basis of the detection of theamount of operations of the shutter mechanism 11 are not normal, thepulse sensor 22 may be out of order, and it cannot be confirmed that theshutter mechanism 11 is in the open state. Therefore, according to theabove configuration, the open state of the shutter mechanism 11 isconfirmed with high accuracy.

Second Embodiment

A description will be given below of a second embodiment of the presentinvention with reference to the accompanying drawings. In the presentembodiment, the mode of confirmation of the open state is different fromthat in the above first embodiment. Accordingly, like or the samereference numerals are given to those components that are like or thesame as the corresponding components of the first embodiment anddetailed explanations are omitted.

As shown in FIG. 4, in the present embodiment, the shutter mechanism 11includes an open position limit switch 23 and a close position limitswitch 24. The open position limit switch 23 is turned ON when theshutter mechanism 11 is at the operation position corresponding to theopen state. The close position limit switch 24 is turned ON when theshutter mechanism 11 is at the operation position corresponding to theclosed state. The phrase “the operation position of the shuttermechanism 11” refers to the rotation position of each movable fin 14that configures the shutter mechanism 11.

Further, the ECU 20 in the present embodiment serves as a positiondetection portion, which detects the operation position of the shuttermechanism 11 on the basis of the operation states of the limit switches(23 and 24), i.e., output signals S1 and S2 of the limit switches (23and 24). The ECU 20, which serves as a confirmation portion, performs anopen state confirmation process after the end of traveling of thevehicle on the basis of the detected operation position.

More specifically, as shown in the flowchart of FIG. 5, if the vehicle 1is in the traveling end state (i.e., YES in step S201), the ECU 20determines whether the open position limit switch 23 is ON based on theoutput signals S1 of the open position limit switch 23 (step S203).

Also, the ECU 20 determines whether the open position limit switch 23 isnormal (step S204). As shown in FIG. 6, in the present embodiment, theopen position limit switch 23 is incorporated into a well-known faultdetection circuit 25. The fault detection circuit 25 includes a firstresistor R1 connected to the open position limit switch 23 in series,and a second resistor R2 connected to the open position limit switch 23in parallel. The ECU 20, which serves as a switch fault detectionportion, detects fault of the open position limit switch 23, morespecifically, the disconnection fault or the short-circuit faultoccurred in the vicinity of the open position limit switch 23 on thebasis of the change of the resistance value R across terminals P1 and P2of the fault detection circuit 25.

That is, in the fault detection circuit 25, the first resistor R1 has acomparatively low resistance value, and the second resistor R2 has acomparatively high resistance value. Accordingly, the resistance value Racross the terminals P1 and P2 is lower when the open position limitswitch 23 is turned ON, and higher when the open position limit switch23 is turned OFF. However, when wiring portions provided nearer theterminals P1 and P2 with respect to the open position limit switch 23are disconnected, the resistance value R is infinite independent of theON or OFF state of the open position limit switch 23. When the shortcircuit occurs in the wiring portions, the resistance value R is zeroindependent of the ON or OFF state of the open position limit switch 23.

The close position limit switch 24 is also incorporated into a faultdetection circuit configured the same as the above fault detectioncircuit 25.

If all the determination conditions shown in steps S203 and S204 aresatisfied (i.e., YES in step S203 and YES in step S204), the ECU 20 inthe present embodiment confirms that the shutter mechanism 11 is in theopen state (step S205). In contrast, if any of the determinationconditions is not satisfied (i.e., NO in step S203 or NO in step S204),the ECU 20 determines that the open state of the shutter mechanism 11cannot be confirmed (step S206).

That is, if the open position limit switch 23 used for detecting theoperation position of the shutter mechanism 11 is out of order, the openstate of the shutter mechanism 11 cannot be confirmed.

If the ECU 20 determines that the open state of the shutter mechanism 11cannot be confirmed (step S206), the ECU 20 controls the shuttermechanism 11 to open the shutter mechanism 11 in the same manner as inthe above first embodiment (steps S207 and S208). If the stop conditionis satisfied (i.e., YES in step S208), the ECU 20 suspends the controlof the shutter mechanism 11 (step S209).

As mentioned above, according to the present embodiment, advantages thesame as those of the above first embodiment can be obtained. Inparticular, in the present embodiment, the open state of the shuttermechanism 11 is confirmed and determined with high accuracy in a simplestructure on the basis of the operation state of the open position limitswitch 23 and the presence/absence of the failure of the open positionlimit switch 23.

Since steps S201 and S202, and steps S207 to S209 in the flowchart ofFIG. 5 are each equivalent to corresponding one of steps S101 and S102,and steps S109 to S111 in the flowchart of FIG. 3, the explanationsthereof are omitted.

Third Embodiment

A description will be given below of a third embodiment of the presentinvention with reference to the accompanying drawings. In the presentembodiment, the mode of confirmation of the open state is different fromthat in the above first embodiment. Accordingly, like or the samereference numerals are given to those components that are like or thesame as the corresponding components of the first embodiment anddetailed explanations are omitted.

In the present embodiment, the ECU 20, which serves as a measurementportion, measures operation time of the shutter mechanism 11 using atimer (not shown) that the ECU 20 includes. The ECU 20, which serves asa confirmation portion, performs an open state confirmation processafter the end of traveling of the vehicle on the basis of the measuredoperation time.

More specifically, as shown in the flowchart of FIG. 7, if the vehicle 1is in the traveling end state (i.e., YES in step S301), the ECU 20determines whether the previous operation of the shutter mechanism 11was the opening operation (step S303). Also, the ECU 20 determineswhether the operation time of the shutter mechanism 11 in the previousoperation was normal (step S304). Specifically, the ECU 20 stores apreset normal operation time, and determines whether the operation timeof the shutter mechanism 11 in the previous operation was the normaloperation time. The phrase “normal operation time” may refer to a valueshowing a single operation time, or values showing an acceptable rangeof the operation time that can be considered as normal.

If all the determination conditions shown in steps S303 and S304 aresatisfied (i.e., YES in step S303 and YES in step S304), the ECU 20confirms that the shutter mechanism 11 is in the open state (step S305).In contrast, if any of the determination conditions is not satisfied(i.e., NO in step S303 or NO in step S304), the ECU 20 determines thatthe open state of the shutter mechanism 11 cannot be confirmed (stepS306).

That is, if the previous operation was not the opening operation, theshutter mechanism 11 is not in the open state. Further, if the operationtime of the shutter mechanism 11 in the immediately previous openingoperation was not normal, the shutter mechanism 11 may not be in theopen state.

If the ECU 20 determines that the open state of the shutter mechanism 11cannot be confirmed (step S306), the ECU 20 controls the shuttermechanism 11 to open the shutter mechanism 11 in the same manner as inthe above first embodiment (steps S307 and S308). If the stop conditionis satisfied (i.e., YES in step S308), the ECU 20 suspends the controlof the shutter mechanism 11 (step S309).

As mentioned above, according to the present embodiment, advantages thesame as those of the above first embodiment can be obtained. Inparticular, in the present embodiment, the open state of the shuttermechanism 11 is confirmed and determined with high accuracy in a simplestructure on the basis of the operation time of the shutter mechanism 11in the immediately previous opening operation.

Since steps S301 and S302, and steps S307 to S309 in the flowchart ofFIG. 7 are each equivalent to corresponding one of steps S101 and S102,and steps S109 to S111 in the flowchart of FIG. 3, the explanationsthereof are omitted.

The above embodiments may be modified as follows.

-   -   In each of the embodiments, the shutter mechanism 11 is provided        in the grill opening 7 through which the air taken into the        engine compartment 3 in the front portion of the body 2 passes.        However, the shutter mechanism 11 is not limited to this. The        shutter mechanism 11 may be provided in a grill opening through        which the air taken into an inner space of the vehicle body 2        other than the engine compartment 3 passes. For example, the        shutter device of the present invention may be applied to        vehicles in which the engine is absent in the space of the        vehicle body forward from the passenger compartment, such as        vehicles in which the engine is arranged in the rear portion or        the central portion of the vehicle body, or an electric vehicle.    -   In each of the above embodiments, the grill opening 7 is formed        below the bumper 8. However, the shutter device of the present        invention is not limited to this. The shutter device may be        applied to a grill opening provided above the bumper 8. That is,        the front grill 9 may be an upper grill.    -   In each of the above embodiments, the shutter mechanism 11 is        opened and closed according to the rotation of each of the        movable fins 14. However, the shutter mechanism is not limited        to this. The shutter mechanism may be of a sliding type as well        as a rotation type as described above, or have a swinging        movable body.    -   In each of the above embodiments, a predetermined stop condition        (steps S110, S208, and S308) regarding the opening operation        control (steps S109, S207, and S307) after the end of traveling        corresponds to a lapse of predetermined time from the start of        the opening operation control. However, the stop condition is        not limited to this. The stop condition may be changed as        necessary.    -   The ECU 20, which serves as a confirmation portion, is        configured to perform the open state confirmation process after        the end of traveling of the vehicle on the basis of the        operation amount of the shutter mechanism 11 in the first        embodiment, the operation position of the shutter mechanism 11        in the second embodiment, and the operation time of the shutter        mechanism 11 in the third embodiment.

That is, in the first embodiment, it is determined whether the previousoperation of the shutter mechanism 11 was the opening operation (stepS103), whether the operation amount of the shutter mechanism 11 in theprevious operation was normal (step S104), whether the pulse has beengenerated after the end of the previous operation of the shuttermechanism 11, and whether the pulse signals Sp are normal (step S106).In the second embodiment, it is determined whether the open positionlimit switch 23 is turned ON (step S203), and whether the open positionlimit switch 23 is normal (step S204). In the third embodiment, it isdetermined whether the previous operation of the shutter mechanism 11was the opening operation (step S303), and whether the operation time ofthe shutter mechanism 11 in the previous operation is normal (stepS304).

However, the mode of the open state confirmation need not be limited tothem. The open state confirmation process may be performed by using anycombination or a single one of the above determination conditionsregarding the confirmation of the open state including otherdetermination conditions.

-   -   The process as shown in the flowchart of FIG. 8 may be        performed. That is, in the same manner as in each of the above        embodiments, when the vehicle 1 is in the traveling end state        (i.e., YES in step S401), the ECU 20 performs the open state        confirmation process (first time) (step S403), and if the open        state cannot be confirmed in the confirmation process (i.e., NO        in step S404), the ECU 20 performs the opening operation control        (steps S405 and S406). In the flowchart of FIG. 8, the ECU 20        performs the open state confirmation process (second time) again        thereafter (step S407). If the open state of the shutter        mechanism 11 cannot be confirmed even in the second time open        state confirmation process (i.e., NO in step S408), the ECU 20        performs the opening operation control again (steps S409 and        S410). Accordingly, the shutter mechanism is more reliably        prevented from being held stopped in the closed state.

In the above flowchart, the first time open state confirmation process(step S403) and the second time open state confirmation process (stepS407) may be different from each other. Also, the first time stopcondition determination process (step S403) and the second time stopcondition determination process (step S407) may be different from eachother.

-   -   In the above first embodiment, the ECU 20, which serves as an        operation amount detection portion, is configured to detect the        operation amount of the shutter mechanism 11 by counting (the        edges of) the pulse signals Sp output by the pulse sensor 22,        which serves as a pulse outputting portion. However, the present        invention is not limited to this. The pulse outputting portion        need not be provided as long as the pulse signals such as        current ripples generated in the motor 18, for example, in        synchronization with the opening and closing operations of the        shutter mechanism 11 can be obtained.    -   The pulse outputting portion need not be the pulse sensor 22        using a Hall IC as in the above first embodiment. The pulse        outputting portion may be the one using an encoder. Further, the        pulse outputting portion may be provided at a position other        than the motor 18 such as a reducer of the actuator portion 12,        for example.    -   The present invention may be configured to determine that it        cannot be confirmed that the shutter mechanism 11 is in the open        state according to a fact that the pulse signals Sp are not        normal even if the fault of the pulse sensor 22 cannot be        specified. Further, the present invention may be configured to        detect the fault of the sensor according to methods other than        the methods described in each of the above embodiments. In this        case, it may be determined that the pulse signals Sp are not        normal according to the detection of the fault of the sensor.    -   In the above second embodiment, the ECU 20, which serves as a        position detection portion, is configured to detect the        operation position of the shutter mechanism 11 on the basis of        the output signals S1 and S2 of the limit switches 23 and 24.        However, the ECU 20 is not limited to this. The ECU 20 may adopt        a configuration in which the absolute position of the shutter        mechanism 11 is detected by counting the pulse signals Sp with a        specific position (for example, full open position) as reference        or using a potentiometer or a magnetic absolute angle sensor.        That is, the open state of the shutter mechanism 11 can be        confirmed with higher accuracy by detecting not only the        operation position corresponding to the open state (or closed        state) but also the absolute position of the shutter mechanism        11.    -   Even in a case where the absolute position is detected, in the        same manner as in the case of detecting the operation amount        (relative position) in the above first embodiment, if a fault of        the pulse signals Sp is detected or if a fault of the sensor is        detected, for example, it may be determined that the open state        of the shutter mechanism 11 cannot be confirmed.    -   In the above second embodiment, the operation position of the        shutter mechanism 11 corresponds to the rotation position of        each of the movable fins 14. However, for example, in the case        of the sliding type shutter mechanism, the traveling position of        each of the fins may correspond to the operation position of the        shutter mechanism 11.    -   In each of the above embodiments, it is recognized that the        vehicle 1 is in the traveling end state (operation end state)        according to a fact that the ignition switch (start switch) of        the vehicle 1 is turned OFF. However, the present invention may        be configured to determine that the vehicle 1 is in the        traveling end state (operation end state) on the basis of the        determination conditions other than the above determination        condition. For example, in vehicles such as an electric vehicle        and a hybrid vehicle, the present invention may be configured        such that it is determined that the vehicle 1 is in the        traveling end state (operation end state) when a master        electrical switch (start switch) is turned OFF.    -   In the above first embodiment, the ECU 20, which serves as a        confirmation portion, is configured to determine that the open        state of the shutter mechanism 11 cannot be confirmed when the        pulse count number in the previous operation is not normal. In        the above third embodiment, the ECU 20 is configured to        determine that the open state of the shutter mechanism 11 cannot        be confirmed when the operation time of the shutter mechanism 11        in the previous operation is not normal. However, the basis of        the open state confirmation is not limited to a value in the        previous operation. The open state confirmation may be performed        on the basis of whether the cumulative value (or average value)        of all the operations of the shutter mechanism 11 until the        vehicle comes into the traveling end state (IG OFF) is normal.

Next, the technical idea that can be obtained from the above embodimentswill be described.

(A) The grill shutter device according to claim 11, wherein the positiondetection portion is configured to detect the absolute position bycounting pulse signals, which are in synchronization with the openingand closing operations of the shutter mechanism, with a specificposition as reference. This allows the absolute position detection withrespect to the operation position of the shutter mechanism with a simplestructure.

(B) The grill shutter device according to any one of claims 1 to 15,wherein the control portion is configured such that it does not performthe opening operation of the shutter mechanism when the open state ofthe shutter mechanism is confirmed by the confirmation portion.

(C) A grill shutter mechanism comprising:

a shutter mechanism adapted to be provided in a grill opening of avehicle body, wherein the shutter mechanism is operable to be opened andclosed to control a flow rate of air flowing into the vehicle body; and

a control portion, which controls opening and closing operations of theshutter mechanism, wherein the control portion is configured to confirmthe open state of the shutter mechanism when a start switch of a vehicleis turned OFF, to control the shutter mechanism to open the shuttermechanism if the open state of the shutter mechanism is not confirmed,and not to perform the opening operation of the shutter mechanism if theopen state of the shutter mechanism is confirmed.

1. A grill shutter device comprising: a shutter mechanism adapted to beprovided in a grill opening in a front portion of a vehicle body,wherein the shutter mechanism is operated to be opened and closed tocontrol a rate of flow of an air flowing into the vehicle body; acontrol portion, which controls opening and closing operations of theshutter mechanism; a traveling end determination portion, whichdetermines whether a vehicle is in a traveling end state; and aconfirmation portion, which confirms that the shutter mechanism is in anopen state in the traveling end state, wherein the control portioncontrols the shutter mechanism to open the shutter mechanism when theopen state of the shutter mechanism is not confirmed by the confirmationportion.
 2. The grill shutter device according to claim 1, furthercomprising an operation amount detection portion, which detects anoperation amount of the shutter mechanism, wherein the confirmationportion confirms that the shutter mechanism is in the open state basedon the operation amount.
 3. The grill shutter device according to claim2, wherein in a case where a previous operation of the shutter mechanismis an opening operation, the confirmation portion determines that theopen state of the shutter mechanism cannot be confirmed if the operationamount in the opening operation is not a preset normal operation amount.4. The grill shutter device according to claim 3, wherein the operationamount detection portion detects the operation amount by counting pulsesignals that are in synchronization with the opening and closingoperations of the shutter mechanism.
 5. The grill shutter deviceaccording to claim 4, further comprising a signal determination portion,which determines whether the pulse signals are normal, wherein theconfirmation portion determines that the open state of the shuttermechanism cannot be confirmed when the signal determination portiondetermines that the pulse signals are not normal.
 6. The grill shutterdevice according to claim 4, further comprising: a pulse outputtingportion, which outputs the pulse signals; and a pulse fault detectionportion, which detects a fault of the pulse outputting portion.
 7. Thegrill shutter device according to claim 4, wherein in a case where theprevious operation of the shutter mechanism is the opening operation,the confirmation portion determines that the open state of the shuttermechanism cannot be confirmed if the operation detection portion detectsthat the pulse signals have been changed after the opening operation. 8.The grill shutter device according to claim 1, further comprising aposition detection portion, which detects an operation position of theshutter mechanism, wherein the confirmation portion confirms that theshutter mechanism is in the open state based on the operation positiondetected by the position detection portion.
 9. The grill shutter deviceaccording to claim 8, further comprising a limit switch providedcorresponding to the open state of the shutter mechanism, wherein theposition detection portion detects an operation position of the shuttermechanism that corresponds to the open state based on an operation stateof the limit switch.
 10. The grill shutter device according to claim 9,further comprising a switch fault detection portion, which detects afault of the limit switch, wherein the confirmation portion determinesthat the open state of the shutter mechanism cannot be confirmed whenthe switch fault detection portion detects a fault of the limit switch.11. The grill shutter device according to claim 8, wherein the positiondetection portion is configured to detect the operation position as anabsolute position.
 12. The grill shutter device according to claim 1,further comprising a measurement portion, which measures operation timeof the shutter mechanism, wherein the confirmation portion confirms thatthe shutter mechanism is in the open state based on the operation time.13. The grill shutter device according to claim 12, wherein in a casewhere the previous operation of the shutter mechanism is an openingoperation, the confirmation portion determines that the open state ofthe shutter mechanism cannot be confirmed if the operation time in theopening operation is not a preset normal operation time.
 14. The grillshutter device according to claim 1, wherein the confirmation portiondetermines that the open state of the shutter mechanism cannot beconfirmed when the previous operation of the shutter mechanism is notthe opening operation.
 15. The grill shutter device according to claim1, wherein if the open state of the shutter mechanism is not confirmedeven after the control portion controlled the shutter mechanism to openthe shutter mechanism in the traveling end state, the control portioncontrols the shutter mechanism to open the shutter mechanism again. 16.The grill shutter device according to claim 11, wherein the positiondetection portion is configured to detect the absolute position bycounting pulse signals, which are in synchronization with the openingand closing operations of the shutter mechanism, with a specificposition as reference.
 17. The grill shutter device according to claim1, wherein the control portion is configured such that it does notperform the opening operation of the shutter mechanism when the openstate of the shutter mechanism is confirmed by the confirmation portion.18. A grill shutter mechanism comprising: a shutter mechanism adapted tobe provided in a grill opening of a vehicle body, wherein the shuttermechanism is operable to be opened and closed to control a flow rate ofair flowing into the vehicle body; and a control portion, which controlsopening and closing operations of the shutter mechanism, wherein thecontrol portion is configured to confirm the open state of the shuttermechanism when a start switch of a vehicle is turned OFF, to control theshutter mechanism to open the shutter mechanism if the open state of theshutter mechanism is not confirmed, and not to perform the openingoperation of the shutter mechanism if the open state of the shuttermechanism is confirmed.